On February 16, 2007 a massive propane release occurred at the Propane De-Asphalting Unit (PDA) of the Valero – McKee Refinery outside Dumas, Texas. The resulting vapor cloud ignited, burning four workers, destroying the PDA, and causing significant knock-on damage to adjacent pipe racks and equipment.

The CSB investigation determined that water trapped in a piping dead-leg froze during cold weather, cracking a 10” diameter liquid propane line and causing the initial release when warmer weather returned. The CSB identified dead-leg identification and management, freeze-protection, and structural steel fire protection as key issues contributing to the incident.

Two near misses were associated with this incident; the release of over 2.5 tons of chlorine from containers adjacent to the PDA, and the inability of workers to access manual deluge valves protecting a nearby LPG storage sphere, which was impacted by the fire.

The CSB made recommendations to Valero, the American Petroleum Institute, the McKee Refinery, and the United Steelworkers and their local.